Question 1203293
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Brandon invested $20 000. He invested part of the money in a term deposit paying 4% annual interest, 
three times as much in a government bond paying 5% annual interest, and the rest in a second mortgage 
paying 7% annual interest. If he earned a total of $1130 interest in one year, how much did he invest at each rate?
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Invested  x         at  4%
         3x         at  5%
and      (20000-4x) at  7%.


Write the total interest equation

    0.04x + 0.05*(3x) + 0.07*(20000-4x) = 1130  dollars.


Simplify and find x

    0.04x + 0.15x + 1400 - 0.28x = 1300

    -0.09x = 1130-1400

     0.09x = 270

     x = 270/0.09 = 27000/9 = 3000.


<U>ANSWER</U>.  $3000 invested at 4%;  3*3000 = 9000 dollars invested at 5%;
         and the rest (20000-3000 - 9000) = 8000 dollars invested at 7%.
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Solved.